1. Imports :

First of all, you just need the following classes to build your own script :

• DefaultCommand : The default class to extend in order to create your own command class.

• BasicProgram : The most simple program to run your command classes.

2. Declaration :

There is a script called sample-program.py which contains all the following lines of code.

1. First you have to create your command class TestCommand. (Step 1)

2. In the __call__ method, you can do every thing you want. The first and only arg of this method is the args object created by Argparse.parser. (Step 2)

3. You create an other class MyProgram (which extends the BasicProgram) (Step 3)

4. Now you create your argparse.parser and your declare your argument, option and command. (Step 4)

5. Finally you just have to instanciate your class MyProgram and run it. (Step 5).

#! /usr/bin/env python2
# -*- coding: utf-8 -*-
# PYTHON_ARGCOMPLETE_OK


from argtoolbox import DefaultCommand
from argtoolbox import BasicProgram

# Step 1
class TestCommand(DefaultCommand):
    """Just a simple command, using the default command class.
    It will print the inputs args to stdout"""

    def __call__(self, args):
        super(TestCommand, self).__call__(args)
        # Step 2
        print ""
        print "This is the beginning of the TestCommand class."
        print "The command line arguments (argv) :"
        print "-----------------------------------"
        print ""
        print "This is the end of the TestCommand class."
        print ""

# Step 3
class MyProgram(BasicProgram):

    def add_commands(self):
        # Step 4
        subparsers = self.parser.add_subparsers()
        parser_tmp = subparsers.add_parser(
            'test',
            help="This command will print cli argv and configuration read \
            from the config file.")
        parser_tmp.add_argument('--host', required=True)
        parser_tmp.add_argument('--port', default=3000)
        parser_tmp.set_defaults(__func__=TestCommand(self.config))


# Step 5
if __name__ == "__main__":

    PROG = MyProgram("sample-program",
                        desc="""Just a description for a sample program.""")
    PROG()

3. Utilisation :

Now you can show the help menu using the following command :

$ ./sample-program.py test -h

Console ouput :

usage: sample-program test [-h] --host HOST [--port PORT]

optional arguments:
  -h, --help   show this help message and exit
  --host HOST
  --port PORT

Or run your command :

$ ./sample-program.py test --host 127.0.0.1

Console ouput :

This is the beginning of the TestCommand class.
The command line arguments (argv) :
-----------------------------------
Namespace(__func__=<__main__.TestCommand object at 0xb721a92c>,
config_file=None, host='127.0.0.1', port=3000, verbose=False)

This is the end of the TestCommand class.

You can see the variable host contains the input message 127.0.0.1 into the args object. The option port contains the default value 3000.

4. Imports :

First of all, you just need the following classes to build your own script :

• TestCommand : This command class will print to stdout the inputs args and the configuration file content.

• BasicProgram : The most simple program to run your command classes.

• SimpleSection : This class is used to declare a Section in the config file (ConfigFile)

• Element : This class is used to declare an Option (a field) in the previous section.

• Base64ElementHook : This hook is used as a post reading processing in order to convert base64 data stored into the config file into plain text data.

5. Declaration :

There is a script called sample-program2.py which contains all the following lines of code.

1. Instead of creating a config file, we will use an in-memory config file (Step 1)

2. You create an other class MyProgram (which extends the BasicProgram) (Step 2)

3. We override the default method called add_config_options. (Step 3)

4. We declare the section named ldap that we are looking for.

5. We declare all the fields store into the previous section. For each fied, you can says if it is required, the default value, the type, an optional description. See the documentatino for more details. (Step 5).

6. The we declare all argparse arguments using the previous configuration declaration. This is very usefull because the data store into the configuration file are used as the default value for the argparse argument. The description, the type, required or not, … declared in the add_config_options method are used to configure the parser argument. No need to repeat your self. (Step 6)

7. Declaration of the test argument using TestCommand class. (Step 7)

8. Finally you just have to instanciate your class MyProgram, the first argument is the program name. (Step 8)

9. We override the default config file name '.<program name>.cfg'. (Step 9)

10. We launch the program. (Step 10)

#! /usr/bin/env python2
# -*- coding: utf-8 -*-
# PYTHON_ARGCOMPLETE_OK

import io
from argtoolbox import TestCommand
from argtoolbox import BasicProgram
from argtoolbox import SimpleSection, Element, Base64ElementHook

# Step 1
SAMPLE_CONFIG = """
[ldap]

host=127.0.0.1
port=389
suffix=dc=nodomain
account=cn=admin,dc=nodomain
password=toto

\n"""

# Step 2
class MyProgram(BasicProgram):

    # Step 3
    def add_config_options(self):
        # Step 4
        # section ldap
        section_ldap = self.config.add_section(SimpleSection("ldap"))
        # Step 5
        section_ldap.add_element(Element('debug',
                                         e_type=int,
                                         default=0,
                                         desc="""debug level : default : 0."""))
        section_ldap.add_element(Element('host',
                                         required=True,
                                         default="192.168.1.1"))
        section_ldap.add_element(Element('account', required=True))
        section_ldap.add_element(Element('port', e_type=int))
        section_ldap.add_element(Element('password',
                                         required=True,
                                         hidden=True,
                                         desc="account password to ldap",
                                         hooks=[Base64ElementHook(), ]))

   def add_commands(self):
        # Step 6
        self.parser.add_argument(
            '--host', **self.config.ldap.host.get_arg_parse_arguments())
        self.parser.add_argument(
            '--port', **self.config.ldap.port.get_arg_parse_arguments())
        self.parser.add_argument(
            '-d',
            action="count",
            **self.config.ldap.debug.get_arg_parse_arguments())

        # Step 7
        subparsers = self.parser.add_subparsers()
        parser_tmp = subparsers.add_parser(
            'test',
            help="This simple command print cli argv and configuration read \
            form config file.")
        parser_tmp.set_defaults(__func__=TestCommand(self.config))


if __name__ ≡ "__main__":

    # Step 8
    PROG = MyProgram("sample-program",
        # Step 9
                     config_file=io.BytesIO(SAMPLE_CONFIG),
                     desc="""Just a description for a sample program.""")
    # Step 10
    PROG()

6. Utilisation :

Now you can run your command :

$ ./sample-program2.py --host an.other.host.com test

Console ouput :

This is the beginning of the TestCommand class.

The loaded configuration :
---------------------------
Configuration of sample-program :

        Section LDAP
         - debug : 0
         - host : 127.0.0.1
         - account : cn=admin,dc=nodomain
         - port : 389
         - password : xxxxxxxx


The command line arguments (argv) :
------------------------------------
Namespace(__func__=<argtoolbox.argtoolbox.TestCommand object at 0xb7199f8c>, config_file=None, debug=0, host='an.other.host.com', port=389, verbose=False)

This is the end of the TestCommand class.

You can see the variable host contains the input message an.other.host.com into the args object. The option port contains the default value 389. You can also acces to the values store into the configuration file like account or password which can not be override by the CLI.